Setting time to live (TTL) in Azure DocumentDB using MongoDB.Driver 2

Question

I'm trying to implement TTL in DocumentDB by using MongoDB.Driver. I created an index like

await collection.Indexes.CreateOneAsync
(
    Builders<T>.IndexKeys.Ascending("_id123"),
    new CreateIndexOptions { ExpireAfter = new TimeSpan(0, 0, 10) }
);

The above code is creating the _id123 index without any errors, but the inserted data is not expiring after 10sec. Please help me to resolve this.

Answer 1

Based on my experience, please have a try to use the _ts field. We can get more information from the document. I do a demo for creating TTL index on my side, it works correctly. The following is the detail steps.

1.Create C# console project and add MongoDB SDK

2.Add a Person Class

using MongoDB.Bson;
public class Person
        {
            public ObjectId Id { get; set; }
            public string Name { get; set; }
        }

3.Create MongodB client and we can get the code from Azure portal.

4.Add document to collection

 var db = mongoClient.GetDatabase("dbname");

 var collection = db.GetCollection<Person>("collectionname");

 collection.InsertOne(new Person() {Name = "tom"});

5.Check from the Azure portal

6.Create TTL index on _ts field

 var indexs = collection.Indexes.CreateOneAsync(Builders<Person>.IndexKeys.Ascending("_ts"),
 new CreateIndexOptions { ExpireAfter = new TimeSpan(0, 0, 10) }).Result;

Package.config file

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="MongoDB.Bson" version="2.4.3" targetFramework="net451" />
  <package id="MongoDB.Driver" version="2.4.3" targetFramework="net451" />
  <package id="MongoDB.Driver.Core" version="2.4.3" targetFramework="net451" />
  <package id="System.Runtime.InteropServices.RuntimeInformation" version="4.3.0" targetFramework="net451" />
</packages>